1: Shell Script condition section if statement to be separated by semicolons
2: test conditions to be noted in the space portion. In both brackets have spaces
3: echo "Hi, $ { a} s" variable is not in single quotes variable substitution operations.
4: [-f "$ file" ] $ file determines whether a file
5: [$ a -lt 3] $ a is determined whether the value of 3, and the same -gt -le represent greater than or equal to less than
6: [ -x "$ file"] and determines whether there is a $ file executable permissions, the same test file -r readability
7: [-n "$ a" ] determines whether a value of the variable $ a, the test string with the empty -z
8: [ "$ a" = "$ b"] Analyzing and $ a $ b values are equal to
9: [cond1 -a cond2] cond1 and determines whether the setting up of cond2, -o represents a cond1 established and cond2
Description: $ # represents the number including $ 0, including the command-line parameters. In the Shell, the name of the script itself is $ 0, followed by the remaining $ 0, $ 1, $ 2 ..., $ {10}, {11} $, and the like. $ * Represents the entire parameter list, not including $ 0, that does not include the parameter list of file names.
Note: Be sure to remember that not a single quotation marks filelist = behind, but the tab key on top of the key, or a key that is left 1
Example: The following shell traverse directory of all files displayfile.sh
cd $1
echo "The Catelog:$1"
files=`ls -a`
m=0
n=0
for f in $files
do
if [ -d "$f" ]; then
m=`expr $m + 1`
else
n=`expr $n + 1`
echo "$f"
fi
done
echo -e "The Catelog Number is $m"
echo -e "The File Number is $n"
运行：./displayfile.sh /home/work
Examples: Linux shell script to determine whether the current user is root
whoami (to display the current user name)IF [ `whoami` =" root "]; the then
"! root user "echo
the else
echo" non-root user! "
Fi
id -u (the current user's uid)
if [ `id -u` -eq 0 ];then
echo "root用户!"
else
echo "非root用户!"
fi
转载于:https://www.cnblogs.com/hubcarl/p/3334008.html